Submersible pump assembly



May 8, 1962 F. w. PLEUGER SUBMERSIBLE PUMP ASSEMBLY 3 Sheets-Sheet 1 Filed June 6, 1958 INVENTOR F. W. P/eu er an oo u oaooco o 0 0 0 ATTOILN E55 F. W. PLEUGER SUBMERSIBLE PUMP ASSEMBLY May 8, 1962 D 3 Sheets-Sheet 2 Filed June 6, 1958 FIG. 3

U O O O O O O O b O O O O O n O O O O O O O O O ATTO L NESS May 8, 1962 w. PLEUGER SUBMERSIBLE PUMP ASSEMBLY 5 Sheets-Sheet 3 Filed June 6, 1958 Ill 4 Fla. 4

ATTGK NEZ'SS 3,033,125 SUBMERSIBLE PUlVIP ASSEMBLY Friedrich W. Pleuger, Hamburg, Germany (Juthornstrasse 80, Hamburg-Wandsbek, Germany) Filed June 6, 1958, Ser. No. 740,393 Claims priority, application Germany June 8, 1957 2 Claims. (Cl. 103--220) This invention relates to submersible pumps, and more particularly to such of the centrifugal type, which are adapted to be used in deep wells submerged under water or other liquids.

The primary object of the invention is to provide a pump assembly, whereby the rotary parts of the pump may be protected against the ingress of sand or similar fine grain substances contained in the pumping liquid. It is known in the art to provide the pump with a screened Opening for the intake of liquid, which is to be pumped up to the surface. Such screens, however, do not grant an efficient protection of the pump against these small particles, which have infiltrated into the pump through the meshes of the screen, and thus obstruct proper operation of the pump, resulting in excessive damages and repair expenses and, finally, in an abridged life time of the pump. Therefore, the present invention is directed to means and methods to eliminate this shortcoming.

A further object of the invention is to provide and arrange in such a submersible pump assembly filter means, whereby any ingress of even finest particles into the pump is prevented.

Another object is the specific manner in which these filter means are constructed.

Still another object are methods and devices whereby deposits in the filter are removed and an increased discharge capacity of the pump is ensured.

The means by which the foregoing and other objects are accomplished and the methods of their accomplishment will readily be understood from the following description on reference to the accompanying drawings of examples which are by no means limiting. In these drawlngs,

FIG. 1 is a partial longitudinal section of a submersible pump assembly in which filter means according to the invention are arranged;

FIG. 2 is a partial longitudinal section of a submersible pump assembly in which the filter means are shown in a modified embodiment;

FIG. 3 is a partial longitudinal section of a submersible pump assembly in which the filter means are shown in still another modification;

FIG. 4 is a view of a pump system embodying the present invention;

FIG. 5 is a view of a second modified form of the pump system.

Referring now to the drawings, in which like numerals are applied to indicate like parts, and more particularly to FIG. 1, the submersible pump unit is formed of one or a plurality of impellers 2, which are mounted on a vertical pump shaft 3 and of which, for the purpose of simplification, one impeller only is shown in the drawing. The pump shaft 3 is connected to and driven by an electric motor arranged below the pump, which motor, as not forming part of the invention, is left out in the drawing.

States Patent erally used bowls between the single stages. In the drawing these bowls are not shown, too. The casing 9 is in connection with the casing of the electric driving motor by means of an intermediate part 10 which forms support of a bearing 11 of the shaft 3. Within the intermediate part 10 a suction passageway 1 for the intake of pumping liquid is housed, having a cylindrical screen 4 at its outer end. In addtiion to the screen 4, a filter 5 is arranged within the passageway 1, which filter 5 is formed of two concentric, perforated sheet covers in isoaxle position visa-vis the shaft 3, the covers being internally lined with gauze 7 of relatively close pores. The hollow formed by the two gauze linings together with the wall of the passageway 1 is filled with loose balls 8 of diameters ranging between approximately 0.5 to 1.5 millimeters, said balls being made of a plastic material such as poly styrol, polyamide, polyvinylchloride, polyethylene, or of a mineral, such as glass, sand, quartz, or of a metal, as for instance stainless steel. The size of the balls 8 depends on the intended use of the submersible pump; the filter is of best permeability with balls of small diameter.

The pores of the gauze linings 7 are smaller than the smallest diameter of the balls 8 so that they cannot be blocked up by these balls.

The aforedscribed filter, which is formed of both the perforated sheet covers 6, their respective gauze linings 7, and of the balls 8, stops even finest sand and other particles and thus makes it impossible for these particles to find a way intothe interior of the pump. The substances passing the fine pores of the gauze linings 7 form deposits within the filter 5, which may from time to time be removed by backfiushing water through the pump. When this measure is taken the deposits in the marginal Zones of the filter are loosened by the filter balls 8, which are in movement during backflushing.

The filter sheets 6 with their coarse perforations consist, for instance, of a metal or a plastic material, and they provide a good permeability and solidity of the whole filter 5, while the filter balls 8 cannot fall out of the filter of the pump in a cartridge-like shape.

- the pump or motor, as this has been set forth in my prior The impellers 2 are enclosed by a casing 9 having the genpatent application, Serial 700,470, dated December 3, 1957.

With reference to FIG. 2, a second, particularly useful arrangement of the filter may be made, instead of in the suction passageway 1, directly in the interior of the pump casing 9 in lieu of one or more impellers 2.; In FIG. 2 the first and second pump stagesare removed, and the space thus gained in the interior of the casing 9 is used to accommodate a filter 21. Said filter is formed of two perforated sheet iron plates 22, which are distanced from each other by two concentric cylinders 23, 24. A fine pore gauze 25, enclosing the filter balls, is placed at the internal surfaces of the perforated plates 22. The filter 21 is tightly fixed in the pump casing 9 between both the rings 26, and it replaces one or mo re pump stages,

Patented May 8, 1962 Such arrangement of the filter in the pump casing is a further improvement in that the filter is well protected and has a large active surface, without it being necessary to modify the other parts of the pump, especially the inter mediate part with its suction pasageway 1. On account of its larger diameter the filter 21 is adapted for service in pumps of relatively large discharge capacity.

If the above plate-shaped filter 21 is insufidcient for the pump capacity one may refer to an arrangement as in FIG. 3, in which four pump stages are replaced by a cylindric filter 31 which is formed of two concentric internally gauze-lined perforated sheet iron sheets 32 and enclosed at both its ends by a ring 33. The hollow in the two perforated cylinders is filled with filter balls in the same manner as in FIGS. 1 and 2 and mounted on an annular disk 34, which has grooves 35 for the passage of water which has entered the pump through the suction passageway 1.

The filter 31 is of a large active diameter, whereby it is adapted for use in pumps with large pumping capacity.

To provide for an escape out of the pump of any fine particles of contaminations which may have penetrated the filter 31, a disk 36 is mounted on the shaft 3, which disk is of approximately the same axial breadth as the fixed disk 34 supporting the filter 31. At its outer circumference, the rotary disk 36 has spiral grooves 37, by which a downwardly directed flow is produced during its rotation, so that any substances that contingently penetrated the filter 31 are retransportcd into the suction passageway 1. This fiow is required to operate against the suctorial pressure within the filter 31 to retransport the particles having passed the filter.

To enforce this latter flow one may arrange below the disk 36 a small impeller 38 of larger diameter than the disk 36, which impeller produces the desired back flow against the suctorial flow in the suction passageway 1. The disk 36 and th impeller 38 may be used alternatively or in cooperation, which depends on the operating condi tions of the pump.

Depending on the degree of impurity of the pumping liquid the pump filter 5, 21 or 31 is gradually blocked up, which results in corresponding decline of the pump discharge capacity. In this case the filter may in a simple manner be cleaned by backflushing water through the pump. A device adapted to meet this purpose is shown in FIG. 4, by way of an example. In the discharge pipe 41, to which the submerged pump assembly 42 in the bore hole is suspended, a back-pressure valve 43 is installed above the earth surface. With the submersible pump systems known in the art this valve is located in the bore hole directly at the pump casing or at the lower end of the discharge pipe. Above the back-pressure valve 43 the discharge pipe 41 is connected by a pipe 44 to a pressure storage tank 45, from which the water pumped up may be conducted to the consumers outlets. In the discharge pipe 41 below the back-pressure valve 43 an air relief cock 46 is located. If one intends to clean the filter of the submersible pump 42 by backfiushing water through it, the air relief cock 46 is opened so that the water column in the discharge pipe 41 regresses down to the water level 47 in the bore hole and thus rinses the filter. If the water level 47 in the bore hole is low enough the water column in the discharge pipe 41 generally is sufficient to rinse the filter to the required extent.

However, if there is a high water level in the bore hole, or if the pump assembly is not lowered deep enough into the water in the hole, the water in the pressure storage tank 45 may additionally be used for rinsing the filter. As shown in FIG. 5, the back-pressure valve 43 above the earth surface is in this case bridged over by a by-pass pipe 48, in which a cutting-off element, for instance a stop valve 49, is arranged. During regular pump operation the valve 49 of the by-pass pipe 48 is locked. To start the rinsing of the filter the pump is stopped, and the valve .49 is opened, whereby all water contained in the pressure storage tank 45 flows back into the pump through pipe 44, by-pas pipe 48, and discharge pipe 41, so that the pump filter is rinsed and cleaned by a large quantity of water.

It is apparent from the above that the backflushing process can be carried out in a simple manner with only a short-tim interruption of operation of the pump 42. When the backfiushing is finished the filter is again in good service condition for some considerable time.

In further simplifying the maintenance of the filter the backfiushing of water through the filter can be carried through automatically as the pump operation is stopped. As an example how this can be accomplished, the air relief cock 45 of the pump system shown in Fl. 4 is provided in such a manner that it is unlocked when there is no more discharge pressure in the discharge pipe 41. This construction is of special benefit where small domestic water supplying pumps are in use. To further improve the cleanage af the filter a pipe conducting compressed water or compressed air may be connected to the air relief cock 46.

Having now described my invention, my claims, the scope of which is not limited to the specific embodiments hereinabove referred to, are:

l. A submersible centrifugal pump assembly, comprising a vertical shaft, a casing having walls enclosing said shaft and means separating the interior of said easing into a plurality of superposed interconnected chambers, a plurality of impellers located in some of said chambers and firmly connected with said shaft for rotation therewith, said impellers constituting the several stages of the pump assembly, a cartridge-like filter removably mounted in another one of said chambers located below the first-mentioned chambers, said filter substantially filling the last mentioned chamber which is devoid of impellers, said cartridge-like filter comprising an inner perforated cylinder enclosing said shaft, an outer perforated cylinder concentrically enclosing said inner perforated cylinder and spaced therefrom and from said walls of the casing, whereby an annular space is formed located between the walls of said casing and said outer perforated cylinder and extending the entire height of said filter, and ballshaped filter bodies filling the space between said perforated cylinders and constituting a loose filling extending between said perforated cylinders, whereby the pumped liquid flows from said outer cylinder through said space and said inner cylinder and then consecutively through said impeller-containing chambers.

2. A submersible centrifugal pump assembly, comprising a vertical shaft, a casing having walls enclosing said shaft and means separating the interior of said casing into a plurality of superposed interconnected chambers, a plurality of impellers located in some of said chambers and firmly connected with said shaft for rotation therewith, said impellers constituting the several stages of the pump assembly, a cartridge-like filter removably mounted in another one of said chambers located below the first-mentioned chambers, said filter substantially fitting the last-mentioned chamber which is devoid of impellers, said cartridge-like filter comprising an inner perforated cylinder enclosing said shaft, an outer perforated cylinder concentrically enclosing said inner perforated cylinder and spaced therefrom and from said walls of the casing, whereby an annular space is formed located between the walls of said casing and said outer perforated cylinder and extending the entire height of said filter and whereby liquid flows unidirectionally from said outer cylinder and through said space and said inner cylinder and then consecutively through said impeller-containing chambers, ball-shaped filter bodies filling the space between said perforated cylinders and constituting a loose filling extending between said perforated cylinders, and a disc mounted upon said shaft and located below said filter, said disc having means causing a flow of said liquid in a direction opposite to that of the flow within said filter.

References Cited in the file of this patent UNITED STATES PATENTS Andrews Aug. 19, 1919 Hollander Aug. 13, 1940 Hayward Nov. 14, 1944 Wright Dec. 25, 1945 10 Albcrtson Apr. 2, 1946 

